title: Coral skeletons provide historical evidence of phosphorus runoff on the great barrier reef.
abstract: Recently, the inshore reefs of the Great Barrier Reef have declined rapidly because of deteriorating water quality. Increased catchment runoff is one potential culprit. The impacts of land-use on coral growth and reef health however are largely circumstantial due to limited long-term data on water quality and reef health. Here we use a 60 year coral core record to show that phosphorus contained in the skeletons (P/Ca) of long-lived, near-shore Porites corals on the Great Barrier Reef correlates with annual records of fertiliser application and particulate phosphorus loads in the adjacent catchment. Skeletal P/Ca also correlates with Ba/Ca, a proxy for fluvial sediment loading, again linking near-shore phosphorus records with river runoff. Coral core records suggest that phosphorus levels increased 8 fold between 1949 and 2008 with the greatest levels coinciding with periods of high fertiliser-phosphorus use. Periods of high P/Ca correspond with intense agricultural activity and increased fertiliser application in the river catchment following agricultural expansion and replanting after cyclone damage. Our results demonstrate how coral P/Ca records can be used to assess terrestrial nutrient loading of vulnerable near-shore reefs.
authors.affiliation: Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia ; Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia.
authors.forename: Jennie
authors.initials: J
authors.lastname: Mallela
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Lewis
authors.forename: Barry
authors.initials: B
authors.lastname: Croke
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000378:metabolism*; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry; D010758:Phosphorus / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000737:chemistry; D060753:Water Quality
chemical_list: D014874:Water Pollutants, Chemical; D010758:Phosphorus